1. Field of the Invention
The invention relates to a writing instrument with a removable closure cap which sealingly closes its writing tip. On the insertion side, the cap has at least one elastically deformable finger extending substantially axially. When the closure cap is in place on the writing instrument, this finger engages an indentation upon the shaft of the writing tip, and an annular shoulder of the writing tip located in the closure cap is in sealing engagement with a sealing shoulder of the closure cap.
2. Brief Description of the Prior Art
In a known writing instrument of this type (German Pat. No. 945 818), a plurality of arms in the form of leaf springs are present in the closure cap, and these leaf springs are curved on their ends nearer the insertion side of the closure cap. This curved end area, when the closure cap is in place on the writing instrument, will grip an annular shoulder of the writing tip from behind. In order to release the closure cap, a special unlocking device is present. By means, and with the aid, of an axially displaceable button, releasing rails are pushed in between the leaf springs and the writing tip, thereby disengaging these elements from one another. Only after this disengagement has been effected can the closure cap be pulled off from the writing tip.
An unlocking device of this kind is not only expensive to fabricate but is also susceptable to failure, because it has parts that are movable counter to spring force.